Open a terminal window : less /System/Library/PrivateFrameworks/AppleAppSupport.framework/Versions/Current/Resources/version.plist

If in there you see a version number that is 1.2 then you have found your problem, it should be version 1.4 and has been causing problems for many.

If you have version 1.2 rather than 1.4 then do the following in terminal : mv /System/Library/PrivateFrameworks/AppleAppSupport.framework /System/Library/PrivateFrameworks/AppleAppSupport.framework.old